The example from application guide for water hammer has forces input in negative X direction only at two bends.This means the unbalanced load is acting only along this direction at the bends ? tIsit because it is not similar to slug force ?he force

A hammer load is an unbalanced pressure wave in a piping leg between elbow-elbow pairs. Therefore the load is axial in that piping leg.

For a slug load, the unbalanced load occurs at the elbows with the change in momentum. The resultant force acts along the bisector of the bend (angle) - hence two (global) load directions.

I have carried out water hammer for one LNG line based on literature in application guide and inputs from process department. Made a write up procedure.
Need your comments. Please advise where to send it for yr guidanceb.
Mr. Richard,need yr mail id for the same.
Regards,
bag_piper

We don't do consulting or approvals. If you want a quick review of your process, open a Support Request on Smart Support and attach the information.

Thx

This particular model was run first and very low frequencies were captured. On the long runs of LNG header there were Line stops which were showing loads like 30 tons ( line size 40 " , LNG, loop at every 45 m ). On either side of line stop 90 m run was there. The surge load was around 100 tons at elbows. In static analysis ,the stops were showing around 55-60 tons load.
Afterwards I have run the dynamic analysis again , with frequency extracted up to 20 Hz. Necessary changes were made in parameters to ensure Sturm check was OK. Suddenly I find that the loads on stops have shot up to say around 200 tons , 150 tons etc.
Is it that there is some problem with the modeling ?
One of the senior colleague opined that water hammer can show such loads.
The load pattern is trapizoidal , 5 ms is valve time , sound velocity is 1200 m/s and fluid velocity is 5 m/s.
Please advice.

There is a mistake , either side of line stop there is a run of 45 to 50 m.

For the example in the application guide, can I analyze the water hammer unbalance forces using only static analysis and applying a DLF instead of performing a time history analysis?

You can use a static equivalent load with a DLF but this approach will not consider the interaction of these many hammers through the system. If each "event" is independent of all the others and you get the right DLF, you are fine with a static approach..